Propeller



- MSAHE A il, BMQBQ, w. A. BELFIELD l PROPELLER Filed Deo, A1.6, 193.6

INVENTOR. @ELF/EL.,

` f f J ATTORNEY.

Bm m, mw W. A. @ELP-HELD www PROPELLER Filed Dec. 1 6, 1956 3 Sheets-Sheet 3 M//LL/AM A, EaP/HD.

ATTORNEY.

ilstranieri olian., 3l,

ariane rnornmnrt This invention has to do with propellers such as are commonly employed as means for driving aircraft, water vessels and the like, and is concerned primarily with propellers designed ior use in aircraft.

The present invention is predicated on the rec-4 ognition that greatest efficiency in the operation of aircraft can be obtained by varying the enactive area of the driving propelier as various conditions such as speed, load, altitude and so`-iorth change.

Accordingly, this invention has in view as its foremost objective the provision oi a propeller which includes two or more blades, the effective area oi which may be varied as occasion demands.,

More particularly the invention has in view as a further objective the provision. of a propeller the character described in which the radial extent of the blades may be varied as circumstances dictate.

in carrying out the above noted objectives in a practical embodiment it becomes necessary to provide for the ready eytension or retraction of the propeller blades, and to this end this invention has in view as a further objective the provi sion of mechanism which may be operated to complete this action on the part of the propeller blades.

More in detail, this invention contemplates availing of the rotary motion of the sha-it on which the propeller is mounted as the source of` power for driving the mechanism which extends or retracts the blades. Inasmuch as there are certain limits to which the blades may be extended or retracted, an important feature of the invention resides in the provision oi safety mechanism for insuring of the discontinuance of power to the extending and retracting mechanism when these limits are reached.

Various other more detailed objects and advantages such as those arising in connection with providing appropriate mechanisms for carrying out the above noted objectives, will in part become apparent, and in part be hereinafter stated, as the description of the invention proceeds.

The invention, therefore, comprises a propeller having extensible blades together with mechanism operable under the inuence of the rotary motion of the shaft on which the propeller is mounted iorextending and retracting the bladeaand this.

mechanism includes-safety devices for discontinu.

uing power to these mechanisms when limits of i extension or retraction have beenreached.

For a full and more complete understanding of the invention, reference may be had to the following description and accompanying drawings wherein Figure i is a side View partly in section and partly in elevation, talren through a propeller and associated mechanism, which is made in accordance with the precepts of this invention. in this view the sectional showing through the propeller hub is teiten on different planes.

Figure 2 is a section taken through one of theA propeller blades, while Figure 3 is a plan view oi a slightly modied form of propeller,

Figure i is a sectional showing taken at right angles to the showing of Figure l. This view is taken about on the plane represented by the line l-i or" Figure l,

Figure 5 is another sectional showing somewhat similar to Figure 4, taken about on the plane represented by the line Bi-- of iiigure i, and

Figure. d is a View somewhat similar to Figure 5, taken on the plane represented by the line d-ii oi Figure i,

` Figure l is an enlarged detailed elevational showing oi the reduction gear assembly,

Figure d is a view similar to i-igure "i, but somewhat diagrammatic, bringing out the direction oi rotation of the gears in the reduction gear assembly, and

Figure 9 isv a section through one of the gear units.

Referring now to the. drawings, wherein. like reference characters denote corresponding parts, a framework intended as a mounting for the propeller oi this 'invention is represented at it. While this framework is primarily intended to be a portion of an aircraft, it is to be clearly underu stood that the invention is not to be limited in this respect, as this propeller might be appropriately mounted in any place where its use is advantageous.

The framework it is provided with a bore at il through which extends a propeller shaft designated li. Itis notable that the framework lll is provided with a tubular extension i3 through which the bore il continues. This sleeve i3 is provided with va keyway i4 for a purpose to be later described.

Mounted at the extremity of the propeller shaft l2 is a hub construction identified as l5, and from which hub project blade stems I6. v At this point it is well to note that while the present invention is illustrated and described in conjunction with a propeller having a pair of diametrically oppositely disposed blade stems I6, the invention is not to be limited in this respect as it may be employed in ditconjunction with any desired number of these blades.

The propeller hub I5 is of a hollow construction providing a recess which is defined by a substantially cylindrical wall I1 and end walls I8 and I9. The end wall I8 is formed with an opening 20, through which passes the shaft I2, while the end wall I9 is formed with a sleeve-like projection 2| which extends inwardly into the recess. This sleeve 2| is formed with a tapered socket 22 which receives the conica.1 end 23 of the propeller shaft I2.

A nut, shown at 24, may be screwed on the threaded extremity 25 of the shaft to maintain the hub I5 assembled on the shaft I2. As shown in Figure 1, a key 26 is fitted in aligned keyways 21 and 28 formed on the hub I5 and conical portion 23 of the shaft I2 respectively, to establish the driving relationship between the hub I5 and shaft I2.

As shown in Figure 2, each of the blade stems I 6 is provided with a central bore 29 which is enlarged adacent to the end of the blade to provide a recess 30, there being a shoulder 3l between the bore 29 and enlarged portion 30. A blade extension is shown at 32, and is formed with a recess 33 which receives the blade stems I6. The blade extensionL 32 is of the usual propeller blade formation, and projecting inwardly from the outer end of the blade extension 32 into the recess33 is aprojection 34 which is slidably received in the recess 30 of the stem I6.

Extending centrally through this projection 34 is athreaded socket 35 which terminates adjacent to the end of the blade extension, as shown at 36.

A shaft shown at 31 is rotatably carried in the bore 29, and held against longitudinal movement in the blade stem I6. The outer portion of this blade 31 is threaded, as shown at 38, and this threaded portion is received in the threaded socket 35 of the extension 32. Theshaft 31 projects inwardly into the recess defined by the cylindrical wall I1, and that portion of the shaft which extends thereinto carries a worm gear 39, and between the worm gear 39 and the extremity of i the shaft 31 the latter carries a plurality of gears identified at 40, which constitute a part of a reduction gear assembly.

These gears 40 cooperate with other gear elements 4I carried by a stub shaft 42 that extends radially outwardly from the shaft I2 to provide a desired gear reduction.

It is to be understood that the number and design of these gear members 40 and 4I will vary as circumstances dictate, but their function is to provide a noticeable reduction so that a gear loosely carried on the end of the shaft 31 will have a greatly reduced rotative movement with respect to the shaft 31. The gears, which are referred to generally as 40 and 4I, comprise a gear 9 of relatively small diameter which is drivably carried by the shaft 31. This gear 9 meshes with the'larger gear 8 of a gear unit comprising a pinion 1 and gear 8. This unit 1 and 8 is rotatably mounted on the stub shaft 42 and the pinion 1 and gear 8 rotate as a unit, and for all functional purposes may be considered as integrally formed.

I'he pinion 1 in turn meshes with a gear 6 that is a part of another gear unit comprising a pinion `5 .and the gear 6. Thus unit 5 6 is rotatably mounted on the shaft 31. The pinion 5 is in mesh with a gear 4 that is a part of a gear unit comprising a pinion 3 and the gear 4, and this unit 3-4 is mounted for rotation on the stub shaft 42. The pinion 'meshes with the gear 2 that is a part of the unit comprising this gear 2 and the gear 43. The unit 2-43 is mounted for rotation on the shaft 31.

The mode of the assembly of the above described reduction gears comprising the parts 40 and 4I is believed to be obvious. Prior to positioning of the propeller shaft I2 in the hub I5 the various gears referred to generally as 40 are assembled on the shaft 31. Thus when the propeller shaft I2 is positioned the extremity of the shaft 31 is so close thereto as to cause the propeller shaft I2 to prevent removal of the gears 40.

A nut referred to as I may be` positioned on one end of the stub shaft 42 to prevent removal of the* gears 4I therefrom. Obviously the end wall I8 of the hub I5 of the propeller may be provided with a suitable opening through which the stub shaft 42 and gearing 4I carried thereby may pass in assembling the shaft I2 in the hub I5.

In each instance a small pinion and large gear, such as the pinion 1 and gear 8 is described as a single unit', and Figure 9 develops this unit when it consists of a single piece of metal machined to the proper formation.

' This gear 43 engages a rack 44 formed as an extension on a sleeve 45 which is carried by the shaft I2; the sleeve 45 being movable axially of the shaft I2. The sleeve 45 is formed at one end with .a flange 46 for a purpose tobe later described.

Themain body portion of the sleeve 45 completely encompasses the shaft I2` and any wellknown key arrangement (not illustrated) may be employed to hold the sleeve 45 against rotation about the shaft I2. Thus the rack 44 is maintained in meshing engagement with the gear 43.

The mechanism above described, and that now to be described is associated with one of the blade stems I6, and as illustrated in the drawings, the drive to the shaft 31 of the other stem I 8 is duplicated at the said other stem. However, there is need for only one of the gearv assemblies 40-'4I so this mechanism is not duplicated.

The end Wall I8 is provided with an opening 41 in which is journaled a shaft 48. The 'shaft 48 terminates in a clutch Velement 56 which takes the form of a diamond toothed clutch member. Cooperating with this clutch member 50 is a complemental clutch element 5I which is carried by a shaft section 52 that is journaled in a recess 53 formed in the wall -I9. A spring 54 encompasses the shaft section 52 and .normally urges the clutch members 50 and 5l into driving engagement. A worm 49 is carried by the shaft section 52 and engages the worm gear 39.

Exteriorally of the hub I5, the shaft 48 drivably carries a pinion 55 that is disposed between an external planetary gear 56 and an internal planetary gear 51. These planetary gears 56 and 51 are carried about the sleeve 45. and each of them is provided -with a braking surface identied at 58v and 59 respectively. A brake band 60 l is associated with the braking surface 58, and another brake band 6I with the braking surface 59.

One end of the brake band 60 is anchored to the frame, as indicated at 62, while the other end represented at 63 is pivotally connected, as shown at 64, to a link at 65. In a like manner one end of the band 6I is anchored tothe frame, as shown at 66, while the other extremity of the band 6I is shown at 61 and is pivotally connected as represented at 68 to a link 69. Ayoke member 10.is crimped about a non-circular extremity 1I of a arsenic yoke member lil are arms i3 and l@ which are pivotally connected to the links 65 and 69 respectively.

The shaft i2 is journaled in an opening i5 formed in a bracket member i6, which is carried by the frame lil.

At the end opposite to the non-circular portion li the shaft 'l2 is reduced in diametrical dimension, and cut away to provide a semi-circular projection l?. This semi-circular projection lli is disposed entirely on one-half of the shaft llt. A second shaft i8 is journaled in an openingl-lii of the framework it, and its free extremity is reduced in a manner similar to the shaft l2 to provide a projection B which overlaps the projection l?.

There is a certain amount of free play between the overlapping projections 'il and 8U, asrepresented at Si in Figure 6. It is evident that the shafts i8 and l2 are in driving relationship with respect to each other, but with a certain amount of free play permitted therebetween.

A collar 82 is rotatably mounted on the projections H and 3l), and at its upper extremity is formed with spaced ears t3 formed with slots dit. An arm 35 is carried by a shaft 85, and projects between the ears 83. A pin Bl is carried by the arm 85 and extends into the slots Ml. Extending from one fiat face of the collar 82 is a projection B8, while a projection 89 extends from the other face, and the function of these projections Bt and SS will later be described.

The shaft 5 is journaled in the frame l@ and bracket i6 respectively, and on each sideof the arm 85 carries collars 90 and 9i to which are anchored springs S2 and 93, for a purpose to be later described.

A sleeve 9d is slidably mounted on the tubular extension i3, and carries a key 95 which projects into the keyway lll to inhibit relative rotative movement of the sleeve Sii. ,At one end the sleeve 94 is provided with an inner annular groove Sii, which receives the ila-nge i6 on the sleeve [55. Upstanding from the sleeve 94 are a pair of wing members 91 and 9B, Awhich are formed with inwardly projecting tongues 99.

A collar l is drivably carried by the shaft section '18, and on each side is provided with spaced ears lill which receive therebetween the tongues 99. The face of the collar HM), which is adjacent to the collar B2, is provided with lugs H12 which are designed to engage the projection 38. It is notable that the spring 92 is anchored to the collar B00, and serves to normally maintain this collar in a definite predermined position.

A second collar HB3, which is similar in all respects to the collar H30, is carried by the shaft section l2. This collar 03 is formed with spaced ears llll which receive the tongues 99, and with lugs at it?) which are adapted to engage the projection 89. l Y

The shaft 38 carries an operating member in the form of a handle l'which is availed of when it is. desired to extend or retract the blade extensions 32.

The operation of the above described mechanism may be briefly outlined by noting that under ordinary conditions the propeler shaft it, sleeve alt, planetary gears S and 5l, propeller hub I5, and all the mechanism carried thereby will rotate with the propeller blades as the latter rotate, to provide the desired driving effects.

Assuming now that one is desirous of extending the blade extensions 32 to their outermost radial position, the lever it will be grasped by the operator, and moved in the direction of the arrow at the left hand side of Figure 6.

At this point it is well to note that with the vblade extensions 32 in their retracted positions,

ti'onship established by projection 8d and lugs im, causes turning of the collar lill). This movement on the part of the collar lili), which is drivably carried by the shaft section it, causes rotation ofthe latter, and through the connection of the overlapping projections 'H and causes rotation of the shaft section l2. This rotation or rocking of the shaft section l1 causes a lowering movement of the arm 'it and an upraising movement of the arm lli. l

The rst mentioned lowering movement of the arm 'i3 releases the brake band Ell, while the upriaisingr of the .arm 'lll tightens the brake` bands di. As the brake band El is tightened the planetary gear 5l is held against rotation while the gear 5E continues to rotate with the propeller shaft i2. As a result the pinion 55 rides around the planetary gear 5l, and is rotated by this action. This rotation causes a co1- responding movement on the part of the shaft sections i8 and 52, and worm gear 39.

The worm i9 drives the worm gear 39, which is drivably mounted on the shaft 3l, and as the latter is rotated the blade extension 32 is extended. At the same time the reduction gearing il@ and Iii is brought into eifect to cause a slight turning' movement on the part of the gear t3 which engages the rack it to move the sleeve @5 inwardly. As the sleeve l5 is moved inwardly, the sleeve lill is also moved inwardly toward the frame lil, so that when the outer limit of extending of the blade extension 32 is reached, the lugs 88 become free from the lugs H02, whereupon the spring @2 causes the collar lill) to be swungv back. into so-called neutral position, in which both ofthe brake bands im and bl are released.

As the projections 88 become disengaged from the lugs H12, the projections m9. engage the lugs m5, so that when it is desired to retract the blades the lever lt may bemoved in the opposite direction indicated by the arrows at the right-hand side of Figure 6, causing a rotation of the shaft l2 in the opposite direction which releases the brake band 6l and applies the brake band Sli, whereupon operation the exact reverse of that just described takes place.

It is important to note that under ordinary conditions the diamond toothed clutch elements fili and till perform no useful function. However, they are embodied in the construction to provide a safety factor in the event the other mechanism for discontinuing the drive to the shaft @il does not properly function. In that event,`

should the blade extension it reach either of its limits of movement, the shaft section it will be rotated, but the diamond teeth of the clutch elements to and tl will become disengaged to prevent rotation of the shaft section 5t and thereby prevent material damage.

'j 4It is notable that the blade extension @t is yshown as encompassing the. blade section it.

Figure 3 develops the converse of this arrangement, in which a blade extension identified as |01 may be contained within the stem section shown at |08. In all other respects the construction and operation of the parts will be similar to that above described.

While a preferred specific embodiment of the invention is hereinbefore set forth, it is to be clearly understood that I am not to be limited to the exact construction illustrated and described, because various modifications of these.

details may be provided in putting the invention into practice within the purview of the appended claims.

I claim:

l 1. Mechanism of the character described comprising a propeller shaft, a hub assembly drivably carried by the shaft and formed with a recess surrounding said shaft, a propeller stem extending radially outwardly from the hub, a blade extension carried by the propeller stem, a shaft extending`through the stem and having threaded engagement with the blade extension, a worm gear on the inner end of said shaft within said recess, a worm in engagement with said worm gear, said worm being carried by a shaft having a pinion at one end, planetary gearing in engagement with said pinion, there being an internal planetary gearing disposed on one side of the pinion, and an externally disposed gear on the other side, and means for selectively braking either of said planetary gears, said braking means comprising a brake band operatively assembled about each of said planetary gears, each of said brake bands having a fixed end and a movable end, a yoke connected to the said movable ends, a shaft drivably carrying said yoke, operating means for rotating said shaft to cause `a corresponding movement on theA part of the yoke whereby one of said brake bands is tightened about its respective planetary gear while the other brake band is loosened about its respective planetary gear, means for yieldably maintaining said shaft in a neutral position in which both said brake bands are loosened; and blade actuated disconnecting means between said operating means and the said shaft.

2. Apparatus of Ithe character described comprising a propeller shaft, a propeller carried by the shaft including a propeller stem, and a blade extension radially movable with respect thereto, gear mechanism for causing said radial movement of the blade extension, said gear mechanism including a pair of planetary gear members, means for selectively braking one of said planetary gear members to cause effective operation of the gear mechanism, a brake band operatively assembledl about each of said planetary gears, each of said brake bands having a fixed end and a'. movable end, a shaft, connections between said shaft and the movable ends of said brake bands whereby rotative movement of the shaft causes a tightening of one brake band and a loosening of the other, yieldable means for maintaining said shaft in a neutral position in which both of said brake bands are loosened, anoperating member, driving'connections between said operating member and said shaft whereby saidv operating member may be availed of to rotate the shaft against-the influence of said movable means, and blade actuated disconnecting means between said operating means and the said shaft.

3. Apparatus of the character described comprising a propeller shaft, a'propeller carried by the shaft including a propeller stem, and a blade extension movable with respect thereto, gear mechanism for causing said movement of the blade extension, said gear mechanism including a pair of `planetary gear members, means for selectively braking one of said planetary gear members to cause effective operation of the gear mechanism', and mechanism for releasing said brake when the limit of movement of the blade extension has been reached, said last named mechanism comprising a sleeve disposed about said propeller shaft and movable axially with respect thereto, there being a gear and rack assembly associated with said aforementioned gear mechanism for causing movement of said sleeve incident to movement of the blade extension with respect to the stem, and operative connections between said sleeve and brake means whereby movement of the sleeve causes releasing of the brake means.

4. Apparatus of the character described comprising a propeller shaft, a hub member disposed about said propeller vshaft and formed with a recess about said shaft, a propeller stem extending from said hub, a blade extension on said stem a shaft extending through said stem and having a threaded engagement with the extension of such nature that rotation of the shaft causes .movement of the blade extension with respect to about said propeller shaft and in engagement 'J with the said pinion, a brake band operatively -associated with each of said planetary gears,and

operating connections between said 'lever and brake bands whereby movement of the lever causes application or release of said bands, and A 

